<template>
  <div class="counter-component">
    <div class="counter-btn" @click="minus">-</div>
    <div class="counter-show">
      <input type="text" v-model="number" @keyup="fixNumber">
    </div>
    <div class="counter-btn" @click="add">+</div>
  </div>
</template>

<script>
export default {
  props:{
    max:{
      type:Number,
      default:5
    },
    min:{
      type:Number,
      default:1
    }
  },
  watch:{
    number(){
      console.log('触发自定义事件on-change传给父元素额参数是：'+this.number)
      this.$emit('on-change',this.number)
    }
  },
  methods: {
    fixNumber() {
      let fix;
      if(typeof  this.number==='string'){
        fix=Number(this.number.replace(/\D/g,''))
      }
      else{
        fix=this.number
      }
      if(fix>this.max || fix<this.min) {
        fix=this.min
      }
      this.number=fix
    },
    minus() {
      if(this.number<=this.min){
        return
      }
      this.number--
    },
    add() {
      if(this.number>=this.max){
        return
      }
      this.number++
    }
  },
  data() {
    return {
      number:this.min
    }
  }
}
</script>

<style scoped>
  .counter-component {
    position: relative;
    display: inline-block;
    overflow: hidden;
    vertical-align: middle;
  }
  .counter-show {
    float: left;
  }
  .counter-show input {
    border: none;
    border-top: 1px solid #e3e3e3;
    border-bottom: 1px solid #e3e3e3;
    height: 23px;
    line-height: 23px;
    width: 30px;
    outline: none;
    text-indent: 4px;
  }
  .counter-btn {
    border: 1px solid #e3e3e3;
    float: left;
    height: 25px;
    line-height: 25px;
    width: 25px;
    text-align: center;
    cursor: pointer;
  }
  .counter-btn:hover {
    border-color: #4fc08d;
    background: #4fc08d;
    color: #fff;
  }
</style>
